Patriarch of Moscow and All Rus

Christianity reached Kievan Rus through the Byzantine Church following the 988 CE baptism of Grand Prince Vladimir, and the church in Rus was initially governed as a metropolitanate under the authority of the Patriarch of Constantinople. As the political center of Russian Orthodoxy shifted north to Moscow following the Mongol conquest, and as Moscow's rulers increasingly styled their state the successor to Byzantium after Constantinople's fall to the Ottomans in 1453, pressure grew for the Russian church to gain an independent, patriarchal status matching its political importance.

In 1589, with the consent of the Ecumenical Patriarch of Constantinople, Metropolitan Job of Moscow was elevated to Patriarch, formally establishing the Moscow Patriarchate as the fifth in honor among Orthodox patriarchates. The office's fortunes have tracked Russian political history closely: Peter the Great, distrustful of an independent church authority that might rival the tsar, abolished the patriarchate in 1721 and replaced it with a state-controlled synodal government; the office was restored only in 1917, amid the collapse of tsarist rule, and the early Soviet decades brought severe persecution of the church before a partial accommodation during and after the Second World War.

The Patriarch of Moscow and All Rus is elected by a Local Council (Pomestny Sobor), a body that in its fullest form includes bishops, clergy and lay delegates from across the church, though twentieth-century patriarchal elections were sometimes conducted under close state oversight during the Soviet period, when the government maintained significant influence over church appointments as a condition of the church's toleration.

The Russian Orthodox Church is by a considerable margin the largest Orthodox church by membership, and the Moscow Patriarchate's jurisdiction has historically extended well beyond the borders of the modern Russian state, including Ukraine, Belarus and other territories of the former Russian Empire and Soviet Union. This wide jurisdiction has become a source of serious tension in the twenty-first century: the Ecumenical Patriarch of Constantinople granted autocephaly, full ecclesiastical independence, to a new Orthodox Church of Ukraine in 2019, a move the Moscow Patriarchate rejected as uncanonical, producing a rupture in communion between the two patriarchates and illustrating how jurisdictional disputes between Orthodox churches, which lack a single central authority to arbitrate them, can remain unresolved for extended periods.